A growing demand for resources and competition for land use, especially critical for Europe, is fueling the search for renewable and sustainable products. Innovative, resource-efficient and integrated approaches such as the development of marine biomass fed into integrated biorefineries may bring sustainable and cost-effective solutions to meet the growing needs. Algal biomass is no doubt considered a promising and valuable feedstock for a bio-based economy. Algae are fast-growing aquatic organisms and most of them are autotrophs: they convert sunlight, carbon dioxide, nitrogen and phosphorous (often available in excess) into valuable biomass components, which are of interest for a diverse group of industries, e.g., the food, feed, cosmetics and energy sectors (chapter 1). Despite the large potential of products derived from algae, its cultivation in Europe is still in its early stages and an estimation of the environmental sustainability may guide a further development and scale-up of this sector by highlighting its competitiveness (chapter 2). Chapter 3 illustrates the objectives of this PhD dissertation (addressed in Part I). In Part II, the environmental sustainability (specifically the life cycle resource footprint) of algae production under temperate climate conditions is assessed in an attempt to unravel the bottlenecks of current European production pathways. In chapter 4 and 5, the environmental footprint of microalgae production for higher value applications, and more specific as a feed ingredient, is examined. A first case study concerns an LCA study of microalgae production in Belgium in an innovative cultivation system for aquaculture purposes (chapter 4). Thereafter, the environmental resource footprint of an integrated algal biorefinery located in the Netherlands is assessed (chapter 5). Both case studies consider waste stream mitigation and a comparison was made with the footprint of alternative biomass plants such as soybeans. However, most envFpironmental sustainability assessment methods are rather semi-mature than well-established, which might result in incomplete LCA comparisons. Therefore, Part III of this PhD addresses the need to better quantify the environmental impacts related to surface use, both terrestrial land and sea surface, as this is not straightforward yet in life cycle assessment (LCA). Advanced LCA indicators are proposed in an attempt to better account for the impact of anthropogenic land and sea surface occupation. This development in the field of LCA enables a more fair comparison between the environmental resource footprint of aquatic algae, cultivated on marginal land or in the sea, versus terrestrial crops, of which most of them are grown on fertile land. |
